JP2005275146A - Dry type capsule toner for electrophotography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry type capsule toner for electrophotography which satisfies any one of fixing performance, low-temperature fixing performance, durability, an anti-blocking property and an anti-offset property at a high level, and which forms a high picture quality image with high transparency and superior glossiness. <P>SOLUTION: A capsule toner, having a structure including a core particle containing a binder resin and a colorant, a mold release agent layer formed on the surface of the core particle, and a resin coating layer formed on the surface of the mold release agent layer, is adopted out of capsule toners with various structures. Furthermore, a crystalline polymer with 3.0-3.7 dynamic viscoelasticity which is the natural logarithm value of a storage modulus at 100°C and 25/s angular frequency is used as the binder resin; and further, the resin coating layer is made to contain a synthetic resin with 5.0-6.0 dynamic viscoelasticity which is the natural logarithm value of the storage modulus at 100°C and 25/s angular frequency. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dry capsule toner for electrophotography.

  In general, in an electrophotographic image forming apparatus, an electrostatic latent image is formed on a photoreceptor based on image information, developed with toner, transferred to a transfer material, and subsequently heated and pressurized in a fixing system, An image is formed by fixing and fixing to a transfer material in a limited and extremely short time. In a normal fixing system, a fixing device including a fixing roller and a pressure roller is used.

  In an image forming apparatus, as a developer for developing an electrostatic latent image, a two-component developer composed of toner and carrier, a one-component developer composed only of toner, and the like are used, and image formation is repeatedly performed. At this time, a so-called offset phenomenon that the toner adheres to the fixing / pressure roller without being fixed to the transfer material is likely to occur. Also, carrier, dust, etc. are likely to adhere to the fixing / pressure roller.

  For this reason, the fixing system includes cleaning means such as a cleaning roller and a cleaning brush in order to remove stains on the surface of these rollers, in particular, the fixing portion where the developer image on the transfer material contacts, together with the fixing and pressure rollers. It is common to include. For example, in a fixing system including a fixing roller, a pressure roller, and a cleaning roller, the arrangement thereof, the contact area between the fixing roller and the pressure roller or the width of the fixing region (nip width), the pressing condition, the fixing temperature, the fixing roller, and Fixing conditions are determined by settings such as the surface roughness, material, and process speed of the pressure roller. In particular, the fixing temperature and pressure conditions are optimized, and the toner is designed so that no offset phenomenon occurs when the toner is fixed on the transfer material within a limited time. Further, for the purpose of preventing the offset phenomenon in the fixing portion, the toner is subjected to molecular weight adjustment of the binder resin for toner, addition of various waxes having releasability, or coating. Thus, a toner that does not adhere to the fixing roller at a temperature of 100 ° C. to 250 ° C., preferably 100 to 160 ° C., and can be fixed on the transfer material is designed.

  Recently, the speed-up technology in full-color electrophotography has been remarkably improved, and while the spread of full-color electrophotography as well as monochrome electrophotography is progressing, higher definition and higher image quality of the formed images are required. . To cope with this, it is necessary to design a toner with good fluidity and transferability, uniform charging performance, excellent offset resistance and tracking resistance, and various other functions. A capsule toner in which is coated with a resin layer has been proposed.

  For example, a release agent layer composed of release agent fine particles is provided on the surface of core particles containing a colorant and a thermoplastic resin, and a chargeable resin layer is provided so as to cover the release agent layer on the surface of the release agent layer. Capsule toner (see, for example, Patent Document 1). In Patent Document 1, the release agent layer is covered with a chargeable resin layer to stabilize the chargeability of the toner and improve the fixability to a transfer material. However, this toner has insufficient durability and undergoes shape deformation due to stirring or the like in a developing tank that is a toner-filled container in the image forming apparatus, and the release agent layer is peeled off from the core particles and charged. Peeling of the functional resin layer from the release agent layer is likely to occur. In addition, simply providing a resin layer on the surface of the release agent layer cannot prevent the release agent from bleeding into the resin layer surface (bleed out), so that the toner has fluidity, transferability and durability. The properties of the photosensitive member deteriorate with time, and filming of the photoreceptor is likely to occur.

  In addition, an electron including a colorant, a release agent particle, and a binder resin, and a resin layer made of a capsule resin is provided on the surface of the core particle in which the colorant and the release agent particle are uniformly dispersed in the binder resin. Examples include dry toner for photography (see, for example, Patent Document 2). In Patent Document 2, the physical relationship between the binder resin and the capsule resin is that the flow softening temperature of the resin layer made of the capsule resin is higher by 5 ° C. or more than the flow softening temperature of the binder resin. . With this configuration, a toner that is excellent in offset resistance, durability, and the like and in which filming of the photoreceptor is prevented is provided. Here, the flow softening temperature is a temperature when a certain amount of molten toner passes through an orifice having a certain diameter. When the characteristics are defined by the flow softening temperature, the viscosity changes gradually if it is an amorphous resin, so the regulation is reflected almost accurately, but in the case of a crystalline resin, a sudden viscosity change occurs. The regulation is often not fully reflected and is preferably characterized by its viscosity in a static molten state. Furthermore, from the viewpoint of energy saving, in order to reduce the power consumption in the fixing system, it is desired to lower the fixing temperature, and as a countermeasure, a large amount of crystalline resin is added to the toner. Even if it is prescribed by the above, it is not possible to obtain a toner excellent in various performances. Further, the degree of improvement in durability is not sufficient, and if the resin layer is left in the developing tank of the image forming apparatus for a long period of time, it cannot be avoided that the resin layer peels off.

  In order to improve the low-temperature fixability of the toner, the binder resin itself has been improved. For example, a crystalline polyester containing 0.1 to 10 mol% of a divalent aromatic compound and having a softening point of 80 to 150 ° C. and 40 mol% or more of an aromatic compound having a bisphenol A skeleton as an alcohol component It has been proposed to use a polyester resin composition containing an amorphous resin using a monomer to be contained as a binder resin for toner (see, for example, Patent Document 3). In Patent Document 3, an attempt is made to improve the compatibility between the crystalline polyester and the amorphous polyester, and although a certain degree of improvement has been achieved, it is not fully satisfactory. Therefore, when a toner is manufactured by a pulverization method using this binder resin, a boundary between the crystalline resin and the amorphous resin appears on or near the toner surface. There is a disadvantage that the performance varies, and the storage stability of the toner is poor.

  In view of such a current situation, image quality performance such as image density and glossiness, and fixing to transfer materials such as durability and fixability are taken into account by taking into account the rheological design that takes into account the dynamic viscoelastic properties of the toner. Attempts have been made to obtain capsule toners that combine the above-mentioned performance at a high level and are excellent in total balance.

  The viscoelasticity value that is an index of the dynamic viscoelastic properties of the binder resin and the toner is, for example, a constant strain and temperature in a molten state in a temperature range higher by 30 ° C. than the glass transition point (Tg) of the binder resin. It is obtained by measuring the angular frequency dependence of storage elastic modulus G ′ (ω), loss elastic modulus G ″ (ω) and dynamic viscosity η * (ω) under the conditions. The storage elastic modulus G ′ (ω) and loss elastic modulus G ″ (ω) of a resin having high meltability, such as a binder resin used in a toner, are usually obtained by measuring the steady viscosity (η). High temperature dependence. Further, when the angular frequency is constant and the temperature is changed, the slopes of the graphs in which the values are plotted for each temperature are greatly different. At this time, the ratio of G ′ (ω) to G ″ (ω) is called a loss tangent tan δ (= G ″ / G ′), and shows a small value in a low temperature range or a high angular velocity range, and a high temperature range or low Increases in the angular frequency range. The dynamic viscoelastic characteristics can also be expressed by a storage viscosity η ′ (ω) indicating a dashpot-like property (viscosity) and a loss viscosity η ″ (ω) indicating a spring-like property.

As the capsule toner considering the dynamic viscoelasticity, for example, in the electrostatic image developing toner in which the surface of the core particle is embedded and coated with a coating particle mainly composed of a synthetic resin and having a diameter smaller than that of the core particle, In order to improve the low-temperature fixability, heat resistance, offset resistance, etc. of the toner, the storage viscosity η ′ (ω) of the core particles is set to 1.5 × 10 ^{4 to} 1.0 × 10 ⁵ poise (95 ° C.) and There has been proposed a toner in which a mechanical tangent loss tan δ, which is a ratio of storage viscosity to loss viscosity (η ′ / η ″), is set to 1.0 to 2.0 (105 ° C.) (for example, Patent Documents). Here, the storage viscosity η ′ (ω) that defines the viscous properties of the toner is the ratio of the loss modulus G ″ (ω) at the angular frequency ω = 100 / s. From this storage viscosity and mechanical tangent loss value, G ′ (ω) is estimated to be in the range of 7.5 × 10 ^{5 to} 5.0 × 10 ⁶ Pa. With such a storage viscosity, fixing at a sufficiently low temperature around 120 ° C. cannot be performed.

  Further, there has been proposed an image forming toner containing a binder resin and a foaming agent and having a maximum value of a mechanical tangent loss tan δ of 2.15 or less at an angular velocity of 100 rad / s and a temperature of 130 to 190 ° C. (for example, (See Patent Document 5). In Patent Document 5, by setting the mechanical tangent loss in the above-described range, improvement in toner fixing property, image density, color developing property, and the like is achieved. However, the mechanical tangent loss is merely the ratio between the storage elastic modulus G ′ and the loss elastic modulus G ″, and the image quality (particularly glossiness) varies greatly depending on the actual value of the storage elastic modulus or loss elastic modulus. Therefore, just being in the above range does not always give a good image.

JP-A-6-130726 JP-A-2001-324831 JP 2002-284866 A Japanese Patent Laid-Open No. 1-219846 JP 2003-43731 A

  An object of the present invention is to provide a dry capsule toner for electrophotography that is excellent in durability, offset resistance, blocking resistance, low-temperature fixability, etc., has high image quality, and can form an image with particularly good gloss. That is.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has obtained a core toner containing only a release resin layer and a resin layer on the surface of the core particle containing a binder resin and a colorant. If the viscoelastic properties of the core particles and the viscoelastic properties of the capsule resin contained in the resin layer have a specific relationship, rather than only specifying the viscoelastic properties, the desired capsule toner can be obtained. The headline and the present invention were completed.

The present invention relates to a core particle containing a binder resin and a colorant, a release agent layer formed on the surface of the core particle, and a coating layer formed of organic particles containing a synthetic resin formed on the surface of the release agent layer. In an electrophotographic dry capsule toner containing
The binder resin is a crystal whose dynamic viscoelasticity represented by the natural logarithm of storage modulus is 3.0 to 3.7 (3.0 or more and 3.7 or less) at 100 ° C. and an angular frequency of 25 / s. The synthetic resin which is an adhesive resin and is contained in the organic particles has a dynamic viscoelasticity represented by a natural logarithm of storage elastic modulus of 5.0 to 6.0 (5. An electrophotographic dry capsule toner characterized in that it is 0 or more and 6.0 or less.

  The dry capsule toner for electrophotography of the present invention is characterized in that the above-mentioned binder resin has a melting point of 90 ° C. or lower.

  Furthermore, the electrophotographic dry capsule toner of the present invention is characterized in that the loss tangent of the synthetic resin contained in the binder resin and the organic particles is 2 to 3 (2 or more and 3 or less), respectively.

  Furthermore, the dry capsule toner for electrophotography of the present invention is characterized in that the crystalline resin is a crystalline polyester resin.

  According to the present invention, in a capsule toner in which a release agent layer and a coating layer are sequentially formed on the surface of core particles containing a binder resin and a colorant, the natural logarithm of storage elastic modulus G ′ ( log G ′) (hereinafter referred to simply as “viscoelastic modulus” unless otherwise specified), a crystalline resin (preferably a crystalline polyester resin) having a specific range is used, and a coating layer is formed. By using a synthetic resin having a specific range of viscoelasticity larger than that of the crystalline resin as the encapsulating resin contained in the organic particles, a dry capsule toner that can be suitably used as an electrophotographic toner is provided. Is done.

  That is, in the present invention, a crystalline resin (preferably a crystalline polyester resin) having a viscoelasticity sufficiently lower than the viscoelasticity of the encapsulating resin contained in the coating layer is used as the binder resin in the core particles. As a result, the binder resin is sufficiently melted and the coating layer can be easily realized in an unmelted state, so that not only low-temperature fixability can be achieved, but also a toner excellent in blocking resistance and durability can be obtained. Further, since the release agent layer is interposed between the core particle and the coating layer, the offset resistance is improved over a wide temperature range. In the present invention, by forming a resin layer having a specific viscoelasticity on the surface of the release agent layer, the seepage of the release agent to the coating layer surface during toner storage is suppressed as much as possible. Therefore, offset resistance can be improved with almost no loss of fluidity, transferability, durability, and the like.

  Therefore, the electrophotographic dry capsule toner of the present invention can be fused, deformed, resin layer or release agent layer between toners even when held in a developing tank which is a toner-filled container in an image forming apparatus for a long period of time. It can be fixed on transfer materials at a fixing temperature of 120 ° C, which is much lower than the conventional temperature, without causing peeling, cracking, and adhesion to the heat and pressure roller. A highly reliable image can be formed with low power consumption.

  Also, the electrophotographic dry capsule toner of the present invention can reduce the content of the release agent compared to the conventional capsule toner, so that the transparency of the image is further improved and the occurrence of filming is further reduced. To do. Although the content of the release agent is small, the offset resistance is superior to the conventional capsule toner.

  Furthermore, according to the present invention, by using a crystalline resin having the above-mentioned viscoelastic modulus and a melting point (Tm, ° C) of 90 ° C or lower as the binder resin, the low-temperature fixability is further improved. The glossiness of the image is further increased.

  Furthermore, according to the present invention, a binder resin and a capsule in which the loss tangent tan δ, which is the ratio (G ″ / G ′) of the storage elastic modulus (G ′) to the loss elastic modulus (G ″), is in the range of 2 to 3. By using a fluorinated resin, further improvement in blocking resistance, offset resistance, durability and the like can be desired.

  The electrophotographic capsule toner of the present invention has a release agent layer and a coating layer formed on the surface of core particles.

  The core particle includes a binder resin and a colorant. The core particle can further contain a charge control agent, a release agent and the like.

[Binder resin]
The binder resin is a crystalline resin. In the present specification, “crystalline” means that the ratio of the softening point to the maximum peak temperature of heat of fusion (softening point / maximum peak temperature of heat of fusion) is 0.9 or more and less than 1.1 in the resin. Preferably it means 0.98 to 1.05. “Amorphous” means that the ratio of the softening point to the maximum peak temperature of heat of fusion is 1.1 to 4.0, preferably 1.5 to 3.0.

  The softening point of the crystalline resin is preferably 85 to 150 ° C, more preferably 90 to 140 ° C, and particularly preferably 95 to 130 ° C. The maximum peak temperature of the heat of fusion of the crystalline resin is preferably 77 to 150 ° C, more preferably 90 to 140 ° C, and particularly preferably 110 to 130 ° C.

  A crystalline resin having such crystallinity has a value of dynamic viscoelasticity expressed by a natural logarithm value (log G ′) of a storage elastic modulus G ′ at a temperature of 100 ° C. and an angular frequency ω = 25 / s. 3.0 to 3.7, preferably more than 3 and less than 3.7. If it is less than 3.0, the durability of the toner is lowered, and when subjected to stirring or the like in the developing tank of the image forming apparatus, deformation or the like is likely to occur, and the release agent layer and / or the resin layer easily peel off. . On the other hand, if it exceeds 3.7, the fixability in a temperature range of about 120 ° C. effective for reducing power consumption becomes insufficient.

  A general binder resin used for the toner has a dynamic viscoelasticity represented by a natural logarithm (log G ′) of the storage elastic modulus G ′ of 4 to 6 at 100 ° C., and is used in the present invention. It is different from what you do.

  In the crystalline resin used in the present invention, the reason why the angular frequency ω is set to 25 / s in defining the dynamic viscoelasticity of the resin is as follows. In general, the heating and pressing time in the image forming apparatus is extremely short. For example, in an image forming apparatus in which the fixing process speed of toner is 117 mm / s and the fixing area (nip width) with respect to the direction of progress of the fixing process is 5 mm, the heating and pressing time is estimated to be about 0.04 / s. Therefore, the present inventor has found that it is desirable to estimate the melting state of the toner from the result of the viscoelasticity measurement corresponding to the instantaneous shear deformation near the fixing time. As a result of further research based on this finding, it has been found that dynamic viscoelasticity at an angular frequency ω = 25 / s is an index that has the greatest influence on the toner fixability in the fixing process. As a result of further research, by setting the binder resin as a crystalline resin, the dynamic viscoelasticity of the binder resin at an angular frequency ω = 25 / s and a temperature of 100 ° C. is set within the specific range. The present invention has succeeded in obtaining a capsule toner excellent in low-temperature fixability and fulfilling the purpose.

  Usually, the toner is a composition containing almost 90% by weight of the total amount of a binder resin, several weight% of a pigment, a release agent, and the like, and further containing a charge control agent and a wax component as necessary. . The dynamic viscoelasticity of the toner itself is substantially determined by the setting of the dynamic viscoelasticity of the binder resin, and is finely adjusted with a pigment, a release agent, and other components. Therefore, by selecting the binder resin and adjusting the content of components other than the binder resin as necessary, it has the dynamic viscoelasticity defined in the present invention, has excellent low-temperature fixability, and has high gloss. A capsule toner capable of forming an image having a feeling can be obtained.

  Further, the crystalline resin used in the present invention preferably has a melting point (Tm) of 90 ° C. or less, and more preferably less than 90 ° C. The crystalline resin has a crystalline region called a domain, and the domain melts as soon as the temperature becomes higher than the melting point of the resin. However, in the temperature range below the melting point, the crystalline resin has a higher elastic modulus than other parts. Exists. Therefore, the storage modulus G ′ of the crystalline resin suddenly decreases before and after the melting temperature (melting point), and its behavior changes significantly. On the other hand, in the present invention, since the fixing temperature is aimed at fixing the toner at a temperature around 120 ° C., which is significantly lower than the conventional temperature, if the melting point of the crystalline resin is around 120 ° C., During fixing, the behavior of the crystalline resin may change abruptly, and fixing may not proceed smoothly. When the melting point of the crystalline resin is set to 90 ° C. or lower, the crystalline resin is in a stable molten state at a fixing temperature of about 120 ° C., so that the possibility of hindering fixing is further reduced. Therefore, the use of a crystalline resin having a melting point (Tm) of 90 ° C. or lower further improves the low-temperature fixability of the capsule toner of the present invention.

  The crystalline resin used in the present invention preferably has a loss tangent (tan δ), that is, a ratio (G ″ / G ′) of storage elastic modulus G ′ to loss elastic modulus G ″ of 2 to 3, More preferably, it is more than 2 and less than 3. If it is less than 2, low-temperature fixability, fixability to a transfer material, and offset resistance may deteriorate. If it exceeds 3, durability, blocking resistance, offset resistance and the like may be reduced. Here, the storage elastic modulus G ′ and the loss elastic modulus G ″ are values at a temperature of 100 ° C. and an angular frequency ω = 25 / s.

  As the crystalline resin, those commonly used in this field can be used, and examples thereof include crystalline polyester, crystalline polyester polyamide, and crystalline polyamide. Among these, crystalline polyester is preferable.

  The crystalline polyester is preferably a polycondensation product of an alcohol component and a carboxylic acid component.

  As the alcohol component, an aliphatic diol is preferable. The number of carbon atoms of the aliphatic diol is preferably 2-6, more preferably 4-6. Specific examples of the aliphatic diol include, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neo Examples include pentyl glycol and 1,4-butenediol. Among these, α, ω-linear alkanediol is preferable, and 1,4-butanediol and 1,6-hexanediol are more preferable. The content of the aliphatic diol is not particularly limited and can be appropriately selected from a wide range, but is preferably 80 mol% or more, more preferably 85 to 100 mol%, particularly preferably 90 to 100 mol%, based on the total amount of alcohol components. .

Examples of the alcohol component other than the aliphatic diol include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4). -Divalent aromatic alcohols such as alkylene (carbon number 2 to 3) oxide (average number of added moles 1 to 10) adduct of bisphenol A such as hydroxyphenyl) propane, 3 such as glycerin, pentaerythritol, trimethylolpropane, etc. Examples include alcohols having a value higher than the value.
The alcohol component can be used alone or in combination of two or more.

  As the carboxylic acid component, an aliphatic dicarboxylic acid compound is preferable. The carbon number of the aliphatic dicarboxylic acid compound is preferably 2 to 8, more preferably 4 to 6. Specific examples of the aliphatic dicarboxylic acid compound include aliphatic carboxylic acids and aliphatic carboxylic acids such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, and adipic acid. Examples thereof include anhydrides and aliphatic carboxylic acid C1-4 alkyl esters. Among these, aliphatic carboxylic acids are preferable. The content of the aliphatic dicarboxylic acid compound is not particularly limited and can be appropriately selected from a wide range, but is preferably 80 mol% or more, more preferably 85 to 100 mol%, particularly preferably 90 to 100 mol, based on the total amount of the carboxylic acid component. %.

Examples of the carboxylic acid component other than the aliphatic dicarboxylic acid compound include aliphatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, and aliphatics such as sebacic acid, azelaic acid, n-dodecyl succinic acid, and n-dodecenyl succinic acid. Examples thereof include alicyclic dicarboxylic acids such as dicarboxylic acid and cyclohexanedicarboxylic acid, trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides thereof, and C1-3 alkyl esters.
A carboxylic acid component can be used individually by 1 type, or can use 2 or more types together.

  The condensation polymerization of the alcohol component and the carboxylic acid component can be performed according to a known method. For example, the reaction may be performed at 120 to 230 ° C. in an inert gas atmosphere in the presence of an esterification catalyst, a polymerization inhibitor, or the like as necessary.

  What is necessary is just to select and use what has a characteristic prescribed | regulated to this invention from these crystalline resins. In addition, the type and amount of monomer used may be appropriately selected to produce a crystalline resin having the characteristics defined in the present invention. A crystalline resin can be used individually by 1 type, or can use 2 or more types together.

  Furthermore, a synthetic resin conventionally used as a binder resin for toner can be used in combination as long as the characteristics of the crystalline resin used in the present invention are not impaired. Examples of the synthetic resin include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, Styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid ester copolymer, styrene-α -Styrenic resins such as methyl chloroacrylate copolymer, styrene-acrylonitrile-acrylate ester copolymer, amorphous polyester resin, epoxy resin, urethane modified epoxy resin, silicone modified epoxy resin, vinyl chloride resin, rosin modified Maleic resin, Phenyl resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, etc. Is mentioned. Among these, styrene-acrylic ester resins, styrene-methacrylic ester resins, crystalline polyester resins and the like are preferable. Further, from the viewpoint of the characteristics of the synthetic resin, those having a glass transition temperature of 50 to 75 ° C. and a flow softening temperature of 100 to 150 ° C. are preferable, and those having a glass transition temperature of 50 to 65 ° C. and a flow softening temperature of 100 to 120 ° C. preferable.

[Colorant]
As the colorant, those commonly used in this field can be used, and examples thereof include organic pigments, inorganic pigments, organic dyes, and inorganic dyes.

  Specific examples of the colorant include, for example, black pigments such as carbon black, copper oxide, iron trioxide, manganese dioxide, aniline black, activated carbon, yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, Yellow pigments such as nickel titanium yellow, navelous yellow, naphthol yellow S, banza yellow G, banza yellow 10G, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, tartrazine lake, red yellow lead, molybdenum orange , Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange, Indanthrene Brilliant Orange RK, Benzidine Orange G, Indanthrene Brilliant Orange GKM, etc. Orange Pigment, Bengala, Cadmium Red Red, such as red lead, mercury sulfide, cadmium, permanent red 4R, risor red, pyrozolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B -Based pigments, purple pigments such as manganese purple, fast violet B, methyl violet lake, bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, fast sky blue, indus Blue pigments such as Ren Blue BC, green faces such as chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green G , Zinc oxide, titanium oxide, antimony white, white pigments such as zinc sulfide, barite powder, barium carbonate, clay, silica, white carbon, talc, extender pigments such as alumina white. Examples of various dyes such as basic, acidic, disperse, and direct dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue. These colorants can be used alone or in combination of two or more. The content of these colorants in the core particles is not particularly limited, but is preferably 1 to 20 parts by weight, more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin. If the amount is less than 1 part by weight, an image having a sufficient image density may not be obtained. On the other hand, if it exceeds 20 parts by weight, the physical properties of the core particles may be insufficient.

  In addition to the above colorants, Hansa Yellow 5G (C.I. 11660), Hansa Yellow 3G (C.I. 11670), Hansa Yellow GR (C.I. 11730), Hansa Yellow A (C.I. 11735) , Hansa Yellow NR (C.I. 11740), Hansa Yellow R (C.I. 12710), Pigment Yellow L (C.I. 12720), Benzidine Yellow (C.I. 21090), Vulcan Fast Yellow 5 (C.I. 21220), Vulcan Fast Yellow R (C.I. 21135) and other yellow pigments, Stalin I (C.I. 12055), Permanent Orange (C.I. 12075), Resol Fast Orange 3GL (C.I. 12175) ), Permanent Orange GTR (C.I. 12305), Hansa Yellow 3R (C.I.) 11725), Vulcan Fast Orange GG (C.I. 21165), Benzidine Orange G (C.I. 21110), Para Red (C.I. 1270), Fire Red (C.I. 12085), Brilliant Fast Scarlet (C Permanent Red F2R (C.I. 12310), Permanent Red F4R (C.I. 12335), Permanent Red FRL (C.I. 12440), Permanent Red FRLL (C.I. 12460), Red pigments such as Permanent Red F4RH (C.I. 12420), Light Fast Red Toner B (C.I. 12450), and Permanent Carmine FB (C.I. 12490) can also be used. These pigments can be used alone or in combination of two or more. Although the content of these colorants in the core particles is not particularly limited, it is preferably 5 to 15 parts by weight, more preferably 6 to 12 parts by weight with respect to 100 parts by weight of the binder resin. If it is less than 5 parts by weight, an image having a sufficient image density may not be obtained. On the other hand, if it exceeds 15 parts by weight, the physical properties of the core particles may be insufficient.

[Charge control agent]
The charge control agent is not particularly limited as long as it can give a positive or negative charge by frictional charging, and various organic or inorganic substances commonly used in this field can be used.

  Examples of the positive charge control agent include Sudan Chief Schwarz BB (Solvent Black 3: Color Index 26150), Fettschwarz HBN (C.I.NO. 26150), alkoxylated amine, alkylamide, molybdate chelate pigment, and the like. It is done. Also, nigrosine base EX (trade name, manufactured by Orient Chemical Co., Ltd.), quaternary ammonium salt P-51 (trade name, manufactured by Orient Chemical Industry Co., Ltd.), nigrosine bontron N-01 (trade name, Orient, Inc.) Commercial products such as Chemical Industry Co., Ltd., Brilliant Spirits Schwarz TN (trade name, manufactured by Farben Fabrikken Bayer), and Zavon Schwartz X (trade name, manufactured by Farberge Hoechst) can also be used. Among these, the quaternary ammonium salt P-51 is preferable.

  Examples of negative charge control agents include oil black (Color Index 26150), thioindigo pigments, and sulfonylamine derivatives of copper phthalocyanine. Oil Black BY (trade name, manufactured by Orient Chemical Industries, Ltd.), Bontron S-22 (trade name, manufactured by Orient Chemical Industries, Ltd.), salicylic acid metal complex E-81 (trade name, Orient Chemical Industries, Ltd.) )), Spiron Black TRH (trade name, manufactured by Hodogaya Chemical Co., Ltd.), Bontron S-34 (trade name, manufactured by Orient Chemical Industry Co., Ltd.), Nigrosine SO (trade name, Orient Chemical Industry Co., Ltd.) ), Ceres Schwartz (R) G (trade name, manufactured by Farben Fabricen Bayer), Chromogen Schwarz ETOO (trade name, CI No. 14645), Azo Oil Black (R) (trade name) , Manufactured by National Aniline). Among these, salicylic acid metal complex E-81 is preferable.

A charge control agent can be used individually by 1 type, or can use 2 or more types together.
Although the content of the charge control agent in the core particles is not particularly limited, it is preferably 0.001 to 5 parts by weight, preferably 0.001 to 3 parts by weight with respect to 100 parts by weight of the binder resin.

[Release agent]
By adding the release agent to the core particles, the release agent inside the core particles sufficiently oozes out to the surface even when relatively high energy is required for fixing, such as when forming images on thin paper. Since offset is prevented, it can be used widely for various transfer materials.

  The mold release agent used in the present invention has a softening point (melting point) which is an endothermic main peak value in a DSC endothermic curve measured by “DSC120” manufactured by Seiko Electronics Co., Ltd., preferably from 40 to 130 ° C., preferably from 50 to 120 ° C. belongs to. When the softening point is less than 40 ° C., the toner has insufficient blocking resistance and shape retention, and when the softening point exceeds 130 ° C., the effect of lowering the fixing temperature or fixing pressure is small.

  Examples of such a release agent include paraffin wax, polyolefin wax, modified wax having an aromatic group, hydrocarbon compound having an alicyclic group, natural wax, and a long chain having an aliphatic hydrocarbon chain having 12 or more carbon atoms. Chain carboxylic acid, its ester fatty acid metal salt, fatty acid acid, fatty acid bisacid etc., paraffin wax such as beeswax, carnauba wax, montan wax, low molecular weight polypropylene, low molecular weight polyethylene, oxidized polypropylene, oxidized polyethylene Preferred are polyolefin waxes such as zinc stearate, calcium stearate, magnesium stearate, zinc oleate, zinc palmitate and magnesium palmitate. Furthermore, those that are incompatible with the binder resin are preferred. The incompatible release agent is one having a large difference in solubility parameter value (SP value) from the binder resin, preferably 0.5 or more. For example, when a crystalline polyester having an SP value of 10.3 is used as the binder resin, examples of the release agent include polyethylene wax (SP value 7.9), polypropylene wax (SP value 7.8 to 8.0), and the like. Is more preferable. Further, the SP value difference with the binder resin is large, and the difference between the softening point (melting point) of the release agent and the flow softening temperature of the binder resin is particularly preferably within 30 ° C.

  In the present invention, a commercially available release agent can also be used. Commercially available paraffin waxes include, for example, paraffin wax, microwax (all trade names, manufactured by Nippon Oil Co., Ltd.), paraffin wax, microcrystalline wax, and hard paraffin wax (all trade names, Nippon Seiwa Co., Ltd.). )), PE-130 (trade name, manufactured by Hoechst), Mitsui High Wax 110P, Mitsui High Wax 220P, Mitsui High Wax 660P, Mitsui High Wax 210P, Mitsui High Wax 320P, Mitsui High Wax 410P, Mitsui High Wax 420P , Modified wax JC-1141, modified wax JC-2130, modified wax JC-4020, modified wax JC-1142, modified wax JC-5020 (all trade names, manufactured by Mitsui Chemicals, Inc.) and the like. Commercially available polyolefin waxes include Hoechst Wax PE520, Hoechst Wax PE130, Hoechst Wax PE190 (all trade names, manufactured by Hoechst), Mitsui High Wax 200, Mitsui High Wax 210, Mitsui High Wax 210M, Mitsui High Wax 220. , Mitsui High Wax 220M (all trade names, manufactured by Mitsui Chemicals, Inc.), Sun Wax 131-P, Sun Wax 151-P, Sun Wax 161-P (All trade names, manufactured by Sanyo Chemical Industries, Ltd.) Non-oxidized polyethylene wax such as Hoechst Wax PED121, Hoechst Wax PED153, Hoechst Wax PED521, Hoechst Wax PED522, Ceridust 3620, Ce idust VP130, Ceridust VP5905, Ceridust VP9615A, Ceridust TM9610F, Ceridust 3715 (all trade names, manufactured by Hoechst), Mitsui High Wax 420M (trade names, manufactured by Mitsui Chemicals), Sunwax E-300 Oxidized polyethylene wax such as Sun Wax E-250P (trade name, manufactured by Sanyo Chemical Industries), Hoechst Wachs PP230 (trade name, manufactured by Hoechst), Biscol 330-P, Biscol 550-P, Biscol Non-oxidized polypropylene wax such as 660P (trade name, manufactured by Sanyo Chemical Industries, Ltd.), and oxidized polypropylene wax such as Piscol TS-200 (trade name, manufactured by Sanyo Chemical Industries, Ltd.) It is done.

  A mold release agent can be used individually by 1 type, or can use 2 or more types together. For example, a plurality of release agents having different softening points can be used.

  The content of the release agent in the core particles is not particularly limited, but is preferably 0.5 to 10 parts by weight, more preferably 2 to 8 parts by weight, and particularly preferably 3 to 7 parts by weight with respect to 100 parts by weight of the binder resin. Part. When the amount of the release agent added to the binder resin is large, the transparency of the image is lowered, and the process member such as the photosensitive member or the developing device is contaminated by filming, which is not preferable.

  In addition, the mold release agent satisfies the above-mentioned use ratio with respect to the synthetic resin, and then, in the core particles, 0.5 to 8% by weight, preferably 2 to 6% by weight, more preferably 3 to 5% of the total amount thereof. It is good to adjust so that it may be contained by weight.

[Other ingredients to core particles]
The core particles can contain additives commonly used in this field, such as magnetic materials and dispersants, as long as the preferable characteristics are not impaired.

  The core particles use a binder resin, a colorant, a charge control agent, a release agent, a magnetic material, a dispersant, etc., and other components are dispersed in the binder resin by kneading and melting, and then pulverized and classified by fine pulverization means. Can be obtained. The average particle diameter of the core particles is not particularly limited, but is preferably 1 μm to 10 μm, more preferably 5 μm to 8 μm. The circularity of the core particles is about 0.70 to 0.90.

[Releasing agent layer]
As the release agent for forming the release agent layer, one or more of the same release agents as those previously added to the core particles can be used.

  As will be described later, the release agent layer can be formed by previously adding a release agent into the core particles and leaching the release agent on the surface of the core particles by hot air spheronization treatment. Regardless of whether or not the core particles contain a release agent, they can also be formed by externally adding a release agent to the core particles and coating the surface of the core particles with the release agent.

  The amount of the release agent used is as described above when internally added to the core particles. Further, in the case of external addition, as in the case of internal addition to the core particles, the amount is preferably 0.5 to 10 parts by weight, more preferably 2 to 8 parts, relative to 100 parts by weight of the binder resin contained in the core particles. Parts by weight.

  The film thickness of the release agent layer is not particularly limited, depending on the usage form of the obtained capsule toner (magnetic, non-magnetic, one component, two components, etc.), the type of binder resin, the type of resin contained in the coating layer, etc. Although it can be selected as appropriate, it is preferably 0.001 to 0.01 μm, more preferably 0.002 to 0.008 μm. In the present invention, the release agent layer can be thinned without degrading the offset resistance, so that it is superior in transparency to conventional encapsulated toners and can be used particularly suitably as a color toner.

[Coating layer]
The coating layer is made of organic particles containing a synthetic resin for encapsulation.
The coating layer is effective in improving the blocking resistance, durability, shape stability during storage, and the like of the capsule toner of the present invention. The coating layer prevents toner blocking, non-uniform charging performance due to shape deformation, and the like during toner storage. On the other hand, at the time of fixing, it is easily broken by the heat fixing roller. Simultaneously with the destruction of the coating layer, the molten release agent elutes instantly, so that the release effect on the heat fixing roller is remarkably exhibited and offset is prevented.

  In the capsule toner of the present invention, although a crystalline resin is used as the binder resin, the crystalline resin includes a crystal domain, becomes brittle at the edge of the domain, and is brittle as a solid. In addition, in order to expand the temperature range in which the offset phenomenon does not occur, a release agent such as polyolefin wax or paraffin wax may be internally added to the binder resin. A sea-island structure in which the mold becomes an island is formed. When core particles are produced by a pulverization method using such a material, a fracture surface is formed at the boundary with the island portion composed of the domain and the release agent, and is exposed to the surface. Since the fracture surface causes fusion, tracking resistance, durability, shape stability during storage, and the like are reduced. In order to prevent this, in the present invention, a coating layer is further formed on the surface of the release agent layer.

  The organic particles have a dynamic viscoelasticity represented by a natural logarithm of storage elastic modulus of 5.0 to 6.0, preferably more than 5.0 and less than 6.0 at 100 ° C. and an angular frequency of 25 / s. Includes synthetic resin for encapsulation. If it is less than 5.0, blocking resistance and durability of the toner (including shape retention during storage) may be deteriorated. On the other hand, if it exceeds 6.0, the fixing property, particularly the low temperature side offset property, may be insufficient.

  The encapsulating synthetic resin preferably has a loss tangent (tan δ), that is, a ratio of loss elastic modulus G ″ to storage elastic modulus G ′ (G ″ / G ′) of 2 to 3, preferably more than 2. More preferably, it is less than 3. If it is less than 2, the fixability and the offset resistance may be lowered. If it exceeds 3, durability, blocking resistance, offset resistance and the like may be reduced. Here, the storage elastic modulus G ′ and the loss elastic modulus G ″ are values at a temperature of 100 ° C. and an angular frequency ω = 25 / s.

  The organic particles are not particularly limited as long as they include a synthetic resin for encapsulation having the above characteristics and have an average particle size smaller than the average particle size of the core particles, preferably 1/5 or less. However, spherical organic particles produced by a soap-free emulsion polymerization method are preferred. In the soap-free emulsion polymerization method, an emulsion radical is removed from the emulsion polymerization system. Initiator radicals generated in the aqueous phase bind monomers that are slightly soluble in the aqueous phase, eventually becoming insoluble and forming particle nuclei. . According to this polymerization method, particles having a narrow particle size distribution are obtained, and the average particle size is also controlled in the range of 0.1 μm to 1 μm. By using organic particles having a uniform average particle diameter, it is possible to form a uniform coating layer with little variation in adhesion between individual organic particles. In addition, since the organic particles formed by soap-free emulsion polymerization are formed without using an emulsifier (surfactant), the influence of moisture as a capsule toner surface layer can be prevented and toner particles having excellent charging stability can be obtained. Moreover, aggregation of organic particles can also be prevented, and generation | occurrence | production of the amount of free fine powder can be prevented.

  The organic particles can be produced according to a general soap-free emulsion polymerization method using a monomer and a polymerization initiator for forming a synthetic resin for encapsulation. At that time, additives such as a colorant and a charge control agent may be added as necessary. In addition, when adding a charge control agent in an organic particle, it is not necessary to add a charge control agent to a core particle.

  The monomer used for the preparation of the organic particles is not particularly limited as long as it can be polymerized by soap-free emulsion polymerization. However, a vinyl monomer, a monomer having a nitrogen-containing polar functional group, fluorine is used. The monomer etc. which have can be used preferably. When the organic particles are composed of a monomer having a nitrogen-containing polar functional group or a monomer having fluorine, the organic particles themselves act as charge control, so even if the amount of the charge control agent in the core particles is reduced, It becomes possible to impart desired chargeability.

  Examples of vinyl monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-ethoxy styrene, p- Styrenes such as phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, ethylene unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, etc. Of vinyl halides, vinyl acetate, vinyl propylene, vinyl benzoate Vinyl esters such as vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, propyl methacrylate, n-octyl methacrylate, methacrylic acid Α-methylene aliphatic monocarboxylic acid such as dodecyl acid, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate Esters, (meth) acrylic acid derivatives such as acrylonitrile and methacrylonitrile acrylamide, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone , N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl compounds such as N-vinyl pyrrolidone, vinyl naphthalenes and the like. Among these, styrenes are preferable, and styrene is more preferable. A vinyl monomer can be used individually by 1 type, or can use 2 or more types together.

The nitrogen-containing polar functional group is effective for positive charge control. Examples of the monomer having a nitrogen-containing polar functional group include, for example, the general formula CH ₂ = C (R ¹ ) -COX-QN (R ² ) ( R ³ )
(In the formula, R ¹ represents hydrogen or a methyl group. R ² and R ³ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. X represents an oxygen atom or a nitrogen atom. Q represents Represents an alkylene group or an arylene group.)
An amino (meth) acrylic monomer represented by Specific examples of amino (meth) acrylic monomers include, for example, N, N-dimethylaminomethyl (meth) acrylate, N, N-diethylaminomethyl (meth) acrylate, and N, N-dimethylamino (meth) acrylate. N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, pN, N-dimethylaminophenyl (meth) acrylate, pN, N-diethylaminophenyl (meth) acrylate, pN, N-dipropylaminophenyl (meth) acrylate, pN, N-dibutylaminophenyl (meth) acrylate, pN-laurylaminophenyl ( (Meth) acrylate, pN-stearylaminophenyl ( ) Acrylate, pN, N-dimethylaminobenzyl (meth) acrylate, pN, N-diethylaminobenzyl (meth) acrylate, pN, N-dipropylaminobenzyl (meth) acrylate, pN, N-dibutylaminobenzyl (meth) acrylate, pN-laurylaminobenzyl (meth) acrylate, pN-staarylaminobenzyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N -Diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, pN, N-dimethylaminophenyl (meth) acrylamide, pN, N -Diethylaminophenyl (meth) a Rilamide, pN, N-dipropylaminophenyl (meth) acrylamide, pN, N-dibutylaminophenyl (meth) acrylamide, pN-laurylaminophenyl (meth) acrylamide, pN-stearylaminophenyl (Meth) acrylamide, pN, N-dimethylaminobenzyl (meth) acrylamide, pN, N-diethylaminobenzyl (meth) acrylamide, pN, N-dipropylaminobenzyl (meth) acrylamide, pN , N-dibutylaminobenzyl (meth) acrylamide, pN-laurylaminobenzyl (meth) acrylamide, pN-stearylaminobenzyl (meth) acrylamide and the like. The monomer which has a nitrogen-containing polar functional group can be used individually by 1 type, or can use 2 or more types together.

  Fluorine atoms are effective for negative charge control, and as fluorine-containing monomers, those commonly used in the production of synthetic resins can be used. For example, 2,2,2-trifluoroethyl acrylate, 2,2,3 , 3-tetrafluoropropyl acrylate, 2,2,3,3,4,4,5,5-octafluoroamyl acrylate, 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate and other fluoroalkyl (meth) acrylates Trifluorochloroethylene, vinylidene fluoride, ethylene trifluoride, tetrafluoroethylene, trifluoropropylene, hexafluoropropene, hexafluoropropylene and the like. Among these, fluoroalkyl (meth) acrylates are preferable. A fluorine-containing monomer can be used individually by 1 type, or can use 2 or more types together.

  The encapsulating synthetic resin contained in the organic particles is preferably a resin having a chemical structure similar to that of the binder resin in the core particles. The glass transition temperature (Tg) of the encapsulating synthetic resin is preferably 50 to 100 ° C., more preferably 60 to 90 ° C., and the flow softening point is preferably 70 to 200 ° C., more preferably 100 to 170 ° C. It is.

  Further, the flow softening point of the encapsulating synthetic resin is preferably 5 ° C. or more higher than the flow softening point of the binder resin of the core particles, and more preferably 20 ° C. to 40 ° C. higher.

  When the organic particles are spherical particles produced by soap-free emulsion polymerization, the average particle size is preferably 0.05 μm to 1 μm, more preferably 0.1 to 0.8 μm, and particularly preferably 0.15 to 0.4 μm. If the average particle size is less than 0.05 μm, there is a possibility that sufficient heat resistance cannot be imparted to the capsule toner. When the average particle size exceeds 1 μm, it becomes difficult to uniformly adhere the organic particles to the surface of the core particles, the surface coverage is lowered, and there is a possibility that the toner cleaning property, durability and the like are not sufficiently improved. Moreover, when it aims at heat resistance provision, it becomes easy to receive to the influence of a colored resin particle. Furthermore, it may be difficult to firmly attach and fix the organic particles to the surface of the core particles.

  The amount of the organic particles used is not particularly limited, but is preferably 5 to 25 parts by weight, more preferably 10 to 20 parts by weight with respect to 100 parts by weight of the core particles.

Moreover, the film thickness of the coating layer formed of organic particles is preferably 0.05 to 1 μm, more preferably 0.1 to 0.6 μm, and particularly preferably 0.15 to 0.35 μm.
Thereby, a capsule toner excellent in blocking resistance and durability can be obtained.

[External additive for electrophotographic dry capsule toner of the present invention]
In order to improve the fluidity of the dry toner for electrophotography of the present invention, a fluidity improver may be added. As the fluidity improver, organic fine powder or inorganic fine powder can be used. Specific examples thereof include, for example, fluorine resin powders such as vinylidene fluoride fine powder and polytetrafluoroethylene fine powder, acrylic resin fine powder, aliphatic metal salts such as zinc stearate, calcium stearate and lead stearate, Surface treatment with metal oxides such as iron oxide, aluminum oxide, titanium oxide, and zinc oxide, wet process silica such as fine powder silica or dry process silica, silica with silane coupling agent, titanium coupling agent, silicon oil, etc. Treated silica and the like. A fluidity improver can be used individually by 1 type, or can use 2 or more types together. Of these, treated silica is preferred. The average particle size of the treated silica is preferably 0.003 to 0.1 μm, more preferably 0.005 to 0.05 μm. Commercially available treated silica can also be used, and examples thereof include Taranox-500 (trade name, manufactured by Tarco) and AEROSILR-972 (trade name, manufactured by Nippon Aerosil Co., Ltd.). The addition amount of the fluidity improver is not particularly limited, but is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the particles after forming the coating layer. . If the amount is less than 0.01 part by weight, the fluidity improving effect may be insufficient. If the amount exceeds 5 parts by weight, fogging, character bleeding, etc. may occur, and the fluidity improving agent may scatter in the image forming apparatus. There is.

[Production of dry capsule toner for electrophotography of the present invention]
The electrophotographic dry capsule toner of the present invention can be produced according to a general method for producing capsule toner.

  For example, a mixing step for uniformly mixing a binder resin and other additives, a dispersion fixing step for obtaining a kneaded product by melting and dispersing other additives in the binder resin, a pulverizing step for pulverizing the kneaded product, A production method (A) comprising a classification step of obtaining core particles by classification, an organic particle attachment step of attaching organic particles to the core particles, an outer shell formation step of forming a release agent layer and a coating layer, and an external additive addition step ), The dry capsule toner for electrophotography of the present invention can be produced. Hereinafter, each process is explained in full detail.

(1) Mixing step An appropriate amount of a crystalline resin, a colorant and a release agent, and, if necessary, additives such as a charge control agent and a dispersing agent are charged into a mixer and mixed uniformly. At that time, a master batch composed of a crystalline resin and a colorant may be prepared, and the master batch and an additive such as a crystalline resin for dilution, a release agent, and a charge control agent may be mixed uniformly. The blending ratio of the masterbatch is binder resin: colored resin = 90: 10-50: 50 (parts by weight), preferably 80: 20-60: 40 (parts by weight). As an example of the blending of each raw material, 20 to 60 parts by weight (preferably 30 to 50 parts by weight) of a masterbatch containing a colorant in the above proportion with respect to 100 parts by weight of the binder resin, 0.5 parts by weight of the mold release agent. 10 parts by weight (preferably 2 to 8 parts by weight), 5 parts by weight or less (preferably 3 parts by weight or less) of the charge control agent, and other appropriate additives such as dispersants can be internally added. The mixer is not particularly limited, and examples thereof include Henschel mixer 20B (trade name, manufactured by Mitsui Mining Co., Ltd.).

(2) Dispersion and fixing step The mixture obtained in the mixing step is melt-kneaded using a melt-kneader to disperse and fix each additive in the crystalline resin. The melt kneader is not particularly limited, and examples thereof include a twin screw kneading extruder such as PCM-30 (trade name, manufactured by Ikekai Kasei Co., Ltd.), TEM-37 (trade name, manufactured by Toshiba Machine Co., Ltd.), KRC. Examples thereof include a continuous kneader such as a kneader (trade name, manufactured by Kurimoto Iron Works Co., Ltd.) and a batch kneader such as a heating / pressure kneader.

(3) Grinding step The kneaded product obtained in the dispersion fixing step is coarsely pulverized to adjust the particle size, and then finely pulverized. The average particle size of the pulverized product is adjusted to about 1 to 10 μm. For fine pulverization, for example, a jet pulverizer such as 200 AFG (trade name, manufactured by Hosokawa Micron Corporation) or IDS-2 (trade name, manufactured by Nippon Pneumatic Industry Co., Ltd.) can be suitably used. Thus, collision fine pulverization with jet air is preferred. Examples of other pulverizers include mechanical pulverizers such as a turbo mill (trade name, manufactured by Kawasaki Heavy Industries, Ltd.) and a super rotor (trade name, manufactured by Nissin Engineering Co., Ltd.).

(4) Classification step Fine powder is removed from the pulverized product obtained in the pulverization step, and classification is performed to narrow the width of the particle size distribution to obtain core particles having a circularity of 0.70 to 0.90. For classification, for example, wind classifier 100ATP (trade name, manufactured by Hosokawa Micron Co., Ltd.), DSX-2 (trade name, manufactured by Nippon Pneumatic Industry Co., Ltd.), Elbow Jet (trade name, Nippon Steel Mining Co., Ltd.) A classification device that performs classification (particle size adjustment) by wind power or rotor rotation can be used.

(5) Organic particle adhesion step A predetermined amount of organic particles is adhered to the surface of the core particles obtained in the classification step and fixed uniformly. Adhesion is performed by a mechanical impact force, a dry mechanochemical method, or the like. The mechanical impact force is given by a shearing force applied from the rotor and the stator in a high-speed air stream, and collision between particles and between the particle and the machine wall. Examples of the fine powder adhesion device using mechanical impact force include a hybridizer NHS-1 (trade name, manufactured by Nara Machinery Co., Ltd.), a cosmos system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like. . The dry mechanochemical method is a method in which organic particles are fixed to the core particle surface by utilizing the heat generated when the particles collide with each other and the apparatus wall member and receive friction, compression, and shearing force. is there. Examples of the fine powder deposition apparatus using the dry mechanochemical method include a mechanofusion apparatus (trade name, manufactured by Hosokawa Micron Corporation), a mechanomill (trade name, manufactured by Okada Seiko Co., Ltd.), and the like.

  At this time, a release agent can be mixed with the core particles together with the organic particles. In this state, when a mechanical impact force is applied, a dry mechanochemical method or the like is performed, only organic particles are selectively attached to the surface of the core particles and fixed.

(6) Outer shell forming step In this step, a release agent layer and a coating layer corresponding to the outer shell of the electrophotographic dry capsule toner of the present invention are formed.

  Specifically, by applying hot air spheronization treatment to the core particles on which the organic particles adhere to the surface, the organic particles are fused to each other to form a coating layer, and between the core particles and the coating layer. A release agent layer is formed on the surface. When hot air spheronization treatment is performed, the binder resin and release agent contained in the core particles melt faster than the organic particles adhering to the surface of the core particles. It is considered that the agent is deposited on the surface of the core particles to form a release agent layer, and then the organic particles are melted to form a coating layer. In the organic particle attaching step (5), even when a release agent is externally added, a release agent layer and a coating layer are sequentially formed on the surface of the core particle in the same manner as described above.

  Here, a release agent that is incompatible with the crystalline resin and has a small difference between the softening temperature and the flow softening temperature of the crystalline resin is used as a synthetic resin for encapsulation contained in the organic particles. It is preferable to use one having a flow softening temperature higher than that of the crystalline resin. By using such a release agent and organic particles, a more uniform release agent layer and coating layer are formed, and preferable properties of the capsule toner of the present invention are further improved.

The hot air spheronization treatment uses, for example, a hot air spheronization device (trade name: Surfing System SFS-3 type, manufactured by Nippon Pneumatic Industry Co., Ltd.), an inlet hot air temperature of 250 to 350 ° C., and a hot air flow rate of 0.6 to 1.5 m ³ / min (hot air cross-sectional area 1.26 × 10 ⁻³ m ² , heat treatment zone length approximately 0.4 m), raw material input amount 0.5 to 1.4 kg / hr, contact time with hot air 0 It is performed under the condition of 0.01 to 1.0 second.

  Further, it is preferable to perform hot air spheronization treatment so that the obtained toner particles have a circularity of 0.93 to 0.99.

  The film thickness of the release agent layer is preferably 0.001 to 0.01 μm, more preferably 0.002 to 0.008 μm. The film thickness of the coating layer is preferably 0.05 to 1 μm, more preferably 0.1 to 0.6 μm, and particularly preferably 0.15 to 0.35 μm.

  The toner particles obtained in this step can be directly used as the electrophotographic dry capsule toner of the present invention.

(7) External Addition Processing Step This step is not an essential step and is performed as necessary. In this step, the toner particles obtained in the outer shell formation step and an appropriate amount of an external additive such as a fluidizing agent are uniformly mixed to obtain the dry toner for electrophotography of the present invention. For mixing, a general mixer can be used, and examples thereof include Henschel mixer 20B (trade name, manufactured by Mitsui Mining Co., Ltd.).

  The dry capsule toner for electrophotography of the present invention can also be obtained by the production method (B) shown below. In the capsule toner of the present invention obtained by the production method (B), the release agent layer does not exist as a clear layer as compared with that obtained by the production method (A), but between the core particles and the coating layer. Since a layer containing a large amount of release agent is formed, the toner has various performances that meet the object of the present invention. In addition, since the clear release agent layer is not formed, the transparency of the toner is further increased, and it can be particularly preferably used as a color toner. Further, according to the production method (B), the amount of free fine powder in the obtained capsule toner can be further reduced, so that the adhesion of the coating layer is further improved, and accordingly, the blocking resistance of the capsule toner, Durability and shape retention during storage are further improved.

  The production method (B) includes a mixing step, a dispersion fixing step, a pulverizing step, a classification step, a release agent layer forming step, a coating layer forming step, and an external addition treatment step, and the release agent layer forming step and the coating layer forming step. Except for the steps, it can be carried out in the same manner as in the production method described above. However, it is not necessary to use a release agent as an essential raw material in the mixing step.

[Releasing agent layer forming step]
In this step, a release agent layer is formed on the surface of the core particles obtained in the classification step. Specifically, a release agent layer is formed on the surface of the core particles by mixing the core particles and the release agent and performing a hot air spheronization treatment. The hot air spheronization treatment can be carried out in the same manner as the hot air spheronization treatment in the above-mentioned production method (5) organic particle adhesion step. As the mold release agent, it is preferable to use one having a melting point equal to or lower than the hot air flow temperature in the hot air spheronization treatment.

  Thereby, a uniform release agent layer having a thickness of 0.001 μm to 0.01 μm, preferably 0.002 μm to 0.005 μm is formed on the surface of the core particle. If a uniform release agent layer is not formed, the organic particles are not sufficiently fixed in the coating layer forming step, which will be described later, and the amount of free fine powder in the resulting capsule toner increases.

[Coating layer forming step]
A predetermined amount of organic particles is uniformly fixed on the surface of the release agent layer of the core particles on which the release layer has been formed in the release agent layer forming step. The organic particles can be immobilized in the same manner as in the case of immobilizing the organic particles on the surface of the core particles in the (5) organic particle adhesion step of the production method (A).

In this manner, the electrophotographic dry capsule toner of the present invention can be obtained.
In the present specification, the physical property values indicating the characteristics of the components are determined as follows.

(Average particle size)
The average particle diameter can be obtained by measuring the relative weight distribution by particle diameter using a 100 μm aperture tube using a Cole Counter TA-II type (manufactured by Cole Counter).

(Flow softening point)
The flow softening point of the binder resin and the encapsulating synthetic resin resin means the temperature at the 50% outflow point measured by an elevated flow tester (trade name: CFT-5000, manufactured by Shimadzu Corporation).

(Softening point)
The softening point (melting point) of the release agent is defined as the softening point (melting point) based on the endothermic main peak value in the DSC endothermic curve measured by a differential scanning calorimeter (trade name: DSC120, manufactured by Seiko Electronics Co., Ltd.).

(Roundness)
The degree of circularity is expressed by the degree of circularity = (circumference of a circle having the same area as the projected area of the particle) / (contour length of the particle projection diagram). FPIA-2000 (trade name, manufactured by Sysmex) It is calculated | required by measuring with the measurement speed of 1500 piece / min.

(Storage elastic modulus G ′ and loss elastic modulus G ″)
A sample (binder resin or encapsulating synthetic resin) 0.8 g was pressed with a tablet molding machine at room temperature (25 ° C.) at about 9.8 × 10 ⁴ Pa (1 kgf / cm ² ) for 30 seconds to obtain a thickness of 1 A measurement sample having a diameter of about 5 mm and a diameter of 25 mm is prepared. This measurement sample was measured with a stress rheometer (manufactured by Rheologica) at a measurement temperature of 100 ° C. to 150 ° C. at intervals of 10 ° C., using a parallel plate, a gap of 1.0 mm, a strain of 3%, and an angular frequency of 100 to 0.1 rad. The measurement was performed under the condition of / s and was shown by the result of the angular frequency 25 / s. The unit is Pa.

  Hereinafter, the present invention will be described more specifically with reference to Examples, Comparative Examples and Test Examples. In the following, “%” and “parts” represent “% by weight” and “parts by weight”, respectively, unless otherwise specified.

  In producing the dry capsule toner for electrophotography of the present invention and comparative examples, the glass transition temperature (Tg, ° C), melting point (Tm, ° C) or flow softening point (Tf, ° C) shown in Table 1, 100 ° C. Crystalline polyester resin having a natural logarithm value (logG ') of storage elastic modulus G' (Pa), a natural logarithm value (logG ") of loss elastic modulus G" (Pa), and a tangent loss (G "/ G ') A1 to A7 (binder resin, trade name: SNG-1C, manufactured by Kao Corporation) and encapsulation synthetic resins B1 to B5 (acrylic resin, trade name: FS series (FS-101, 701), Nippon Paint (Made by Co., Ltd.).

(Example 1)
[Manufacture of core particles]
Crystal polyester resin A3 100 parts Coloring masterbatch (mixture of 70 parts of polyester resin with glass transition temperature Tg = 64 ° C., 4 mm flow softening temperature T4m = 109 ° C. and 40 parts of pigment (CI Pigment Red 122)) 40 Part Negative charge control agent (oxogluco compound, trade name: Copy Charge NCA cp2243, manufactured by Clariant Co., Ltd.) 3 parts The above raw materials are mixed at 2800 rpm by a mixer (trade name: Henschel Mixer 20B, manufactured by Mitsui Mining Co., Ltd.). After uniformly mixing for 5 minutes, the mixture was melt-kneaded with a twin-screw kneading extruder (trade name: PCH-30, manufactured by Ikekai Kasei Co., Ltd.), and the additive was dispersed and fixed in the resin. The kneaded product was left to cool and then coarsely pulverized with a feather mill to obtain a 2 mm mesh pass. Subsequently, it was finely pulverized by a jet pulverizer (trade name: 200 APG, manufactured by Hosokawa Micron Corporation), and classified by an air classifier (trade name: 100 ATP, manufactured by Hosokawa Micron Corporation) to obtain core particles having an average particle diameter of 6 μm. .

[Adhesion of organic particles]
Organic particles B3 comprising 100 parts of core particles, 10 parts of a release agent (polywax, melting point 128 ° C., trade name: Hoechst Wax PE130, manufactured by Hoechst) and a styrene-acrylic copolymer produced by a soap-free emulsion polymerization method. 15 parts by a surface modification device (trade name: Hybridizer NHS-1, manufactured by Nara Machinery Co., Ltd.) at a rotor rotational speed of 90 m / s for 5 minutes, and the core particles are organic particles B3 for capsules. Was attached.

[Formation of release agent layer and coating layer]
Next, the hot air spheronizer (trade name: Surfusing System SFS-3 type, manufactured by Nippon Pneumatic Industry Co., Ltd.) is used for the core particles to which the organic particles B3 for capsules are attached, and the inlet hot air temperature is 320 ° C. , Heat treatment under the conditions of contact time with hot air of 0.03 / s, flow rate of hot air per unit area of 1.0 m ³ / min, input amount of the raw material of 1.0 kg / hour, average particle size of 8 μm, circularity of 0. 95 toner base particles were obtained.

  100 parts of toner base particles and 0.5 parts of silica fine particles (average particle size: 14 mμ, trade name: R-972, manufactured by Nippon Aerosil Co., Ltd.) having a surface hydrophobized are mixed with a mixer (Henschel mixer 20B). The mixture was uniformly mixed at 2800 rpm for 2 minutes to produce the electrophotographic dry toner of the present invention.

(Comparative Examples 1-4)
Toner as in Example 1 except that resin A1 (Comparative Example 1), A2 (Comparative Example 2), A4 (Comparative Example 3) or A5 (Comparative Example 4) is used instead of crystalline polyester resin A3. Manufactured.

(Comparative Examples 5-8)
Toner as in Example 1 except that organic particles B1 (Comparative Example 5), B2 (Comparative Example 6), B4 (Comparative Example 7) or B5 (Comparative Example 8) are used instead of the organic particles B3. Manufactured.

(Example 2)
A toner was manufactured in the same manner as in Example 1 except that the resin A6 was used instead of the crystalline polyester resin A3.

(Comparative Example 9)
A toner was manufactured in the same manner as in Example 1 except that the resin A7 was used instead of the crystalline polyester resin A3.

(Test Example 1)
Two-component developers composed of 5 parts of the toners of Examples 1-2 and Comparative Examples 1-9 and 95 parts of ferrite carrier were prepared, and the following evaluation tests were carried out using the two-component developers. The results are shown in Table 2.

[Fixability]
An image was formed on plain paper using a digital copying machine (trade name: AR-C250, fixing temperature 160 ° C., manufactured by Sharp Corporation) having a resolution of 600 dpi. Bend this plain paper with the printing surface in the middle, then roll the 850g roller back and forth to make a constant pressure, apply a load, and scrape the boundary of the bent portion of the printing surface 5 times with a brush. The fixability test was conducted. The state of the bent portion was observed and evaluated according to the following criteria. Here, let L be the line width of the peeled portion of the toner layer formed in the bent portion. The fixability of the toner mainly depends on the adhesion to paper and the meltability of the toner.
A: The width L is very thin and thin, and the toner layer is well melted and fixed.
A: The width L is less than about 0.3 mm and is a fine line and has a cut.
(Triangle | delta): The width L is about 0.5 mm, a thin line is clear, and a connection is good.
X: The width L is considerably disturbed and the toner layer is not fixed.

[durability]
The developing tank of the digital copying machine (AR-C250) was filled with a two-component developer, and the developing roller was idled (rotated) for 10 hours at the same rotational speed as when image formation was performed. Thereafter, the two-component developer was taken out, the carrier was separated, washed with water and dried. A fixed amount was dissolved in tetrahydrofuran, and the amount of toner adhering to the carrier was quantified by spectral absorption spectrum analysis as the amount of magenta pigment contained in the toner. That is, the maximum absorption wavelength and peak amount of the magenta pigment in the tetrahydrofuran solution were measured (measured values for 10 hours). In addition, the maximum absorption wavelength and peak amount (initial measured value) of the magenta pigment were measured in the same manner before 10 hours idling. Based on the measurement results, the peak rate (peak amount of 10-hour measurement value / peak amount of initial measurement value) was calculated and evaluated according to the following criteria. In addition, the one where a peak rate is lower is excellent in durability.
A: The peak rate is 0.5 or less.
○: The peak rate exceeds 0.5 and is 1 or less.
(Triangle | delta): A peak rate exceeds 1 and is 1.5 or less.
X: The peak rate exceeds 1.5.

[Blocking resistance]
The toner was placed in a constant temperature bath at 50 ° C. and left for 24 hours. The toner particle size distribution before and after that was measured with a Coulter counter to determine the amount of change in particle size distribution (coupling) due to toner aggregation and fusion, and evaluated according to the following criteria. The smaller the coupling, the better the blocking resistance.
A: Coupling is 0.2 μm or less.
○: Coupling exceeds 0.2 μm and is 0.5 μm or less.
(Triangle | delta): Coupling exceeds 0.5 micrometer and is 1.0 micrometer or less.
X: Coupling exceeds 1.0 μm.

[Offset resistance]
The developing tank of the digital copying machine (AR-C250) was filled with a two-component developer, and an image output test was performed. Fixing conditions were set such that the nip width was 5 mm, the process speed was 117 mm / s, and the pressure was 2.3 kg / cm ² . The surface temperature of the fixing roller was changed, and an unfixed image sample having a width of 20 mm × length of 50 mm was passed. The image sample after fixing was visually observed for the presence of an offset, and evaluated according to the following criteria.
A: Fixing is possible within a temperature range of 40 ° C. or higher, and printing does not appear on the white background.
○: Fixing is possible within a temperature range of 30 to 40 ° C., and printing does not appear on the white background.
Δ: Fixing is possible within a temperature range of 20 to 30 ° C., and the print is slightly reflected on the white background.
X: Fixing is possible within a temperature range of 10 to 20 ° C., and printing is clearly reflected on the white background.

[Comprehensive evaluation]
AA: Excellent fixability, durability / blocking resistance / offset resistance are good, and can be used in a very suitable manner.
A: Excellent fixability, good durability and blocking resistance, and may have some difficulty in offset resistance, but there is no problem in practical use.
B: Excellent fixability, almost excellent durability and blocking resistance, and difficult to offset, but can withstand actual use.
C: Durability and blocking resistance are almost good, but the fixing property is slightly inferior, in particular, the fixing property on the low temperature side is inferior, and the offset resistance is insufficient.
D: Fixability is almost good, but durability and blocking resistance are inferior, resulting in a serious problem in actual use.

  From Table 2, it is clear that the dry capsule toner for electrophotography of the present invention has excellent fixability, low temperature fixability, durability, blocking resistance and offset resistance.

Claims (4)

An electron including a core particle containing a binder resin and a colorant, a release agent layer formed on the surface of the core particle, and a coating layer formed on the surface of the release agent layer and made of organic particles containing a synthetic resin In dry capsule toner for photography,
The binder resin is a crystalline resin having a dynamic viscoelasticity represented by a natural logarithm of storage modulus of 3.0 to 3.7 at 100 ° C. and an angular frequency of 25 / s, and is contained in organic particles. The synthetic resin has a dynamic viscoelasticity represented by a natural logarithm of storage elastic modulus of 5.0 to 6.0 at 100 ° C. and an angular frequency of 25 / s, and is a dry capsule toner for electrophotography.   The electrophotographic dry capsule toner according to claim 1, wherein the binder resin has a melting point of 90 ° C or lower.   3. The dry capsule toner for electrophotography according to claim 1, wherein the loss tangent of the synthetic resin contained in the binder resin and the organic particles is 2 to 3, respectively.   The dry capsule toner for electrophotography according to claim 1, wherein the crystalline resin is a crystalline polyester resin.